// $Id: StreamByteSource.java,v 1.4 2005/09/22 03:55:07 kaminw Exp $

/*									tab:4
 * "Copyright (c) 2000-2003 The Regents of the University  of California.  
 * All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose, without fee, and without written agreement is
 * hereby granted, provided that the above copyright notice, the following
 * two paragraphs and the author appear in all copies of this software.
 * 
 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
 * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
 * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS."
 *
 * Copyright (c) 2002-2003 Intel Corporation
 * All rights reserved.
 *
 * This file is distributed under the terms in the attached INTEL-LICENSE     
 * file. If you do not find these files, copies can be found by writing to
 * Intel Research Berkeley, 2150 Shattuck Avenue, Suite 1300, Berkeley, CA, 
 * 94704.  Attention:  Intel License Inquiry.
 */

package tools.packet;

import java.util.*;
import java.io.*;

abstract public class StreamByteSource implements ByteSource {
	protected InputStream is;
	protected OutputStream os;
	private boolean opened;

	protected StreamByteSource() {
	}

	abstract protected void openStreams() throws IOException;

	abstract protected void closeStreams() throws IOException;

	public void open() throws IOException {
		openStreams();
		opened = true;
	}

	public void close() {
		if (opened) {
			opened = false;
			try {
				os.close();
				is.close();
				closeStreams();
			} catch (Exception e) {
			}
		}
	}

	public byte readByte() throws IOException {
		int serialByte;

		if (!opened)
			throw new IOException("not open");

		try {
			serialByte = is.read();
		} catch (IOException e) {
			serialByte = -1;
		}

		if (serialByte == -1) {
			close();
			throw new IOException("read error");
		}

		return (byte) serialByte;
	}

	public void writeBytes(byte[] bytes) throws IOException {
		if (!opened)
			throw new IOException("not open");

		try {
			os.write(bytes);
			os.flush();
		} catch (IOException e) {
			close();
			throw new IOException("write error");
		}
	}
}
